I search the IFHF's online database at ROOTSIRELAND.IE. It has abt 20 M church, civil, census, etc B/M/D records for MOST Irish counties, including Sligo. Records before 1863 are increasingly sparse - almost none before 1800.
For Pat(rick) Queenan B 1829 +/- 20 yrs, Co. Sligo, with the parents' names unknown, I found 0 records. Very few Sligo parish records from this era have survived.